1. Field of the Invention
The invention relates to a torsional vibration damper for arrangement in a drive train of a motor vehicle.
2. Description of the Related Art
For the damping of torsional vibrations in the drive train of an automobile, prior art reference DE 42 00 174 A1 discloses a prior art torsional vibration damper comprising two flywheel mass arrangements which are rotatable both jointly and relative to one another about a common axis of rotation. Coupling mass arrangements that are uniformly distributed about the axis of rotation are used to couple the two flywheel mass arrangements for transmitting torsional forces therebetween. Each of the coupling mass arrangements includes a pendulum weight that is pivotally mounted on a first of the two flywheel mass arrangements about a pivot axis oriented parallel to the axis of rotation. In an operating state in which no torque is transmitted between the two flywheel mass arrangements, the pendulum weight is oriented essentially radially due to the centrifugal force acting on the pendulum weight. Each of the coupling mass arrangements also includes an elongate connecting member which is oriented essentially circumferentially. One end of the elongate member is articulately connected to the second flywheel mass arrangement and the other end of the elongate member is articulately connected to the pendulum weight at a point arranged radially outside the pivot axis of the pendulum weight. A torque to be transmitted between the two flywheel masses during operation introduces a force via the connecting member to the pendulum weight. The force attempts to pivot the pendulum weight about its pivot axis counter to the action of the centrifugal force. The two flywheel mass arrangements rotate relative to one another until an equilibrium is established between the centrifugal force acting on the pendulum weight and the torque transmitted by the connecting member. The relative rotation of the two flywheel mass arrangements is counteracted by a force determined essentially by the inert masses of the two flywheel mass arrangements and of the coupling mass arrangements and by the moments of inertia of the pendulum weights, thereby causing the uncoupling or damping of torque fluctuations.
In this known torsional vibration damper, the torsional vibration damping properties and the profile of the restoring force acting between the two flywheel mass arrangements, which are directed toward the position of equilibrium, are a function of the rotational speed and the rotational deflection of the two flywheel mass arrangements. The torsional vibration damping properties and the profile of the restoring force acting between the two flywheel mass arrangements may be adjusted by changing characteristics of the coupling mass arrangement such, for example, as the length of the connecting member, the distance between the pivot bearing of the pendulum weight and the articulated connection between the pendulum weight and the connecting member, and the mass distribution of the pendulum weight. However, the basic profile of the restoring force is not adaptable to any profile which may be desired, because the restoring force is an invariable function of the rotational speed.